Rheostat



April '19, 1927. 1,625,479

A.k F. C. LOTZ RHEOSTAT Filed March 26. 1925 :s sneetsneef, 1

April 19, 1927.

1,625,479 A. F. c. Lo'rz RHEOSTAT 3 Sheetsfheet 5 A Filed March 26.. 14925 [/zvefa 5799274174505.

lt/w55 es WwW/M Patented Apr. 19, 1927.

UNITE-D STAT Es PAT ENT OFFICE.

ALFREDF. O. LOTz, OF c1IIoAGo,'ILLINOIs, AssIGNoR To riLEccIRIoAL'ENGINEERsr EQUIPMENT COMPANY, OFOIIIOAGO, ILLINOIS,v yli tOomoinvrION OF ILLINOIS.

RHEOSTAT Application filed March 26, '192'51'v seiar'No 18,522/

accurately included to greateror less extent in the circuit toghe Controlled. lOnft'he yac-rI coinpan'ying 'drawings lny nnp'rovecl apparatus isy shown, and on the drawings,

F 1 isa side elevational view WithA the housing vtraine in section;

Fig.' 2 is asectionalview on the plane;I

Q Qpfifig. 1;K I

Fig.l 3 is yan* end elevational vieiv; y Fig. 4 is la' sectional view on plane 4 4 of Fig.2p; o A Figf 5 is a sectional view on plane 5-5 o'f' Fi is a sectionalview on plane `6-G`of Fgl' L ,l lhe ap Jaratus 1s enclosed Within long housin'g yhaving the Wall 10' and the ends 'Walls'll and125/ thev rWall 12 being' shown 1n the'forna of a 'detah'alle cover.`

Wc.. muy.: .11 ...l im'. The ends of the housing are semi-cylindrical and In these ends are arranged the drum i' y L y of the hous1ng-- As shown, the end of the structures A and B.y The ,druinystrufctufre F i i l', l i' i. A comprises the end Wall 13 ofinsulatino.

materiayltliavii'ig the central l'hubl l14"'*and thel cylindrical Aor circumferential part ""15. Af

spider frame 16 seats in the end (if the flange opposite the Wall'13.

A ushingl eXtendsthrough the lhulof14x7 andlieceivs'v thel shaft- 1,8.y y vsleeve' 19i re-y ceives the bushing 117' is 'securedA in' and"k extends from the hub 14and 'j'ust outside of n n J u y v 4 o Wall n12 `when the nut 46k is applied to the` y the traine 16`this sleeve carries the' gear' pinion The* dem Sarraute it "ijs, thugs mounted'tofrotat on 'the Qshalft 18@ l,The shaft outside "of the 'pinidn" 2Q has thel. rev, duced A end f 2x1exten'dingfthiloiiglil th'eh sup porting plate' 22 and fthev fend' is thre'aded;A 'to. receive the 'nu 23 softh'a't @the shaft fina be rigidlz) Sectiredito tliehzfraine`l22 towe'izl end is a sectional view on' Aplane 7`7 of i z i 8 is a sectional viewy on plane 8 8 o't 9 is 'a sectional vieuiv on Xplaire 9?9 yofr The' drufn structure B comprises circular enCVfraines l24 and 25 secured on the hub sleeve 26 which holds the bushing 27 through which` the, druin supporting shaft 28 eX- y tenets;l Qutside of the end Wall 24 the hub sleeve 2G carries the gear pinion 29, and outside oftliis pinion the shaft has the reducedv end 30 extending lthrough the supporting plate 22and: engaged' by the' nut AThe shaft' 28 thus'I extends perpendicularly from t-he "plate 22 andl'paifallel with the 'shaft 18 of the fdriini'A. The vplate 22 may be supported froin theinn'erWa-ll L11y of the 'hous- :t

ingff Asshoiwnfthe shaft ends 21 and 30 extend through the" housing Wall to loe engaged nuts y Interinetliate lits ends the supporting plate 22 'clamped vbetween the end flange 33 of vthe supporting bushing 34 and fthe nut 35 threadingl on'said bushing. This'hushing'" extends through a supporting panelt and clan'i'pss' infla'c'e/ by lock nuts 37. rThrough the Il'qusliiiig@54 extends the main ory controlling shaftsjSS, having atits outer end the knurled knob 89. Between the supporting'plat-e 22and themdruin structure, the shaft has secured thereto the gear 40 Which meshes with therpinionslQO and 29 lof' the respective drun'i 'stri'rct'uresyA so'that When the l knob 39 is turned, the druin'structures will be rotated', and" in the arra'ingei'nent shown, the gear vratio as 34 to 1, the drums perforniing .t-lyii'ee revolutions for each vrevolution lofthe gears() or the main shaft 38. The's'hafts 18and28 may loe supported at their outer endsby the. cover struct'uref12 shaftf 18 extends ythrough a spacer block 41,

`andlje't bushing 42 vextending through the Wall "12, a nut 43engaging the threaded end of throughv block 44 vand lthe' bushing 45, which are caused to clamp vthe housing shaft fend..."y A'bearing block 47,*Inayfalso be loo providedwonft'he housirighivall 1,2V to receive Vand Siupijc i"tT the` outer end of the controller iatelyl arrange these" vvires on the drum, the` cylindrical side is provided with double threading 479. rIhis drum structure is of insulating' material, as has been explained, so that the wire lengths will be insulated from cach other. The cylindrical Wall of the drinn structure B is of electric conductive material, such as brass or copper, and to this drum the ends of the resistance lengths 48 and 48 are anchored in any suitable Way. As shown, a single piece of resistance Wire may be bent intermediate its ends to form the resistance lengths or legs a8 and 48, and at its bend the wire is hooked around the anchor post 5l, as shown in Fig. l. To accon'nnodate the resistance legs and properly space them, the wall 50 has external double threading 52 corresponding with the threading 49 on the drum structure A.

The resistance conductor lengths ai'e thus anchored at one end to a metallic drinn surface and are connected together electrically. At their other ends, the resistance lengths extend through passageivays 53 and 54. in the drum structure A and connect with the terminals 55 and 56 extending into the interior of the drum structure from the commutator or contact rings 57 and 58 secured in the outer wall 13 of the drinn structure A. These contact rings are engaged by the ends of the brushes 59 and 60 extending from the terminal screivs 6l and 62 secured to the housing wall 12 by nuts G3 and insulated from the ivall by insulating members 64. `When the brushes are in engagement with the commutator rings, the circuit connected with the terminals 6l and 62 will include serially the resistance legs 48 and 48', the effective resistance length at any time being that between the connections of the legs With the rings and their engagement point with the cylinder structure B. Referring to Fig. l. the entire resistance of the legs Will be inserted, as the legs are insulated from each other up to their very ends at the anchor post 51. If noiv the knob 39 is turned in clockwise direction (from the left of Fig. l), the drum structures will be rotated in counterclockivise direction and the resistance legs ivill be Wound from the insulating drinn structure A to the metallic drinn structure B, the resistance legs being connected together electrically as they first engage ivith the drum structure B. Then the legs have both been Wound onto the drum` struct-ure B, they ivill offer practically no resistance to the circuits including them. The `ear ratio between the knob shaft and the drinn shaft being as 3 to l, the drinn structures Will be comparatively rapidly rotated upon turning of the knob and the entire resistance range afforded by the resistance legs can be quickly run over. 'Ihe resist-ance increase or decrease is always regular, and as the resistance element cannot Wear or be ivorn down, on account of ,the frictionless winding engagement of the element with the drums, the resistance condition of the element will remain constant. Very line, accurate and dependable resistance adjustment can therefore be quickly and readily made with my device.

It may be desirable to keep the controlled circuit open and to close it only When operation is desired and it is desired to reduce resistance. rLccOrdingly, I have provided an abutment block ('55 which receives the threaded section (iii of the knob shaft 38, the threading on this shaft section being double and corresponding with that on the drinn structures. The block (S5 is held from turningl by its engagement with the drum structures, and at its outer end the block has the cross arm (37 for engaging with the coinniutator brushes 59 and (SO. `When the knob shaft has been tiii'ned to place the drums With the entire resistance effective, the block Will have been shifted along the shaft section 66 to bring its arm 6T against the brushes and then a slight further turn will release the brushes from the commutator ring, so as to open the circuit. `When the knob is now turned in clockwise direction, the iirst movement of its shaft ivill cause withdrawal of the block from the brushes and the brushes will engage With the commutator segments to close the circuit. Further nioveinent then of the knob and drums will include more or less of the resistance legs in circuit. As the drums are revolved to adjust for the desired resistance, the block 65 travels back and forth along the shaft section 66, it being remembered that this shaft turns only one revolution for three revolutions of the drinn shaft, so that the threaded section 66 of the shaft may be comparatively short.

I do not desire to be limited to precisely what I have shoivn and described, as changes and modifications are possible which will still come Within the scope of the. invention.

I claim as follows l. In a device of the class described, thc combination of an insulating cylinder, a unitary conducting cylinder of substantially the same length as said insulating cylinder, apair of parallel resistance conductors, Wound upon said cylinders, each of said cylinders being adapted for receiving substantially the entire ivindable portions of said conductors and said conducting cylinder providing a single variable connection betiveen the conductors, circuit connections for the conductors, and means for turning the cylinders to 'transfer the conductors from one cylinder to the other.

2. In a device of the class described, the combination of a rotatable cylinder, a con'- ductor adapted for winding thereon, a con-- tact on the cylinder and in electrical connection Wit-li said conductor, a contact arm engageable with said contact, means for Winding the conductor upon and unwinding it from said cylinder, and means operable by said last means for disengaging said contact arm from said contact.

In a device of the class described, the combination of an insulating cylinder, a conducting cylinder, resistance conductor means carried by said cylinders, separable contacts for said conductor means, means for turning said cylinders to transfer said conductor means from one cylinder to the other, and means operable by said turning means for separating said contacts.

4;. In a device of the class described, the combination of an insulating cylinder, a conducting cylinder, conductor means carried by said cylinders and adapted to have its effective length varied by said conducting` cylinder, means for turning said cylinders to transfer said conductor from one cylinder to the other, a circuit connection for said conductor, and means operative at the great.

est effective length of said conductor for disconnecting said circuit connection.

5. In a device of the class described, thel combination of a conducting cylinder, an insulating cylinder, conductor means carried by said cylinders and adapted to be Wound from one cylinder to the other, a driving shaft extending between and connected to turn said cylinders, a circuit connect-ion for said conductor means, and a member guided by said cylinders and operable along said shaft for controlling said connection.

6. In a device of the class described, the combination of a conducting cylinder, an insulating cylinder, conductor means carried by said cylinders and adapted to be Wound from one cylinder to the other, a driving shaft extending between and connected to turn said cylinders, circuit connections for said conductor means including a pair of contact arms, one on each side of said shaft and cooperating contacts, andmeans operable along said shaft for disengaging said contact arms from their cooperating contacts.

7. In a device of the class described, the combination of a conducting cylinder, an insulating cylinder, conductor means carried by said cylinders and adapted to be Wound from one cylinder to the other, a driving shaft extending between and connected to turn said cylinders, a circuit connection for said conductor means, and a member operable along said shaft for controlling said connection.

In Witness whereof, I hereunto subscribe my name this 23rd day of March, 1925.

ALFRED F. C. LOTZ. 

